LIMITED USEFULNESS OF TRACTION-COMPRESSION FILMS IN THE RADIOGRAPHIC DIAGNOSIS OF LUMBAR SPINAL INSTABILITY - COMPARISON WITH FLEXION-EXTENSION FILMS

Study Design. A prospective, within patient comparison of two methods for functional radiography of lumbar spine with consecutive patients. Objective. To evaluate the usefulness of traction-compression radiogra phy compared with conventional flexion-extension radiography in diagno sis of lumbar spinal instability. Summary of Background Data. Flexion- extension radiography generally is used and widely recognized as an ef fective method for diagnosis of segmental lumbar spinal instability, b ut the usefulness and findings of traction-compression films are less well known. Methods. Flexion-extension and traction-compression radiog raphy were performed on 306 consecutive patients (mean age, 43 years; range, 14-68 years) with clinically suspected lumbar spinal instabilit y. Radiography was performed of each patient in upright position. Axia l traction was accomplished by letting the patient hang by his or her hands from a horizontal bar. Compression views were taken when the pat ient had sandbags of approximately 30% of the his or her weight on the shoulders. Main interest was translational forward backward displacem ent of one vertebra on another. Results. Signs of translational instab ility were present On the functional radiographs of 27% (84 of 306) of the patients. In diagnosis of instability, the overall agreement of f lexion-extension had fraction-compression films was only 0.786, and al so Statistic Kappa remained poor (0.05). Flexion-extension films more frequently revealed signs of instability than traction-compression fil ms: 81 versus seven patents. Conclusions. Traction-compression films s eem to be of questionable value in diagnosis of lumbar spinal instabil ity.